Color stabilization of vinyl halide resins



"Patented Feli. 15, 19 49 COLOR s'rABnJzA'rIoN or VINYL HALIDE' 1 RESINS Delaware No Drawing. Application June 15, 1945, SerialQNo. 599,770- 7 I 1 "9 Claims. (01. 260-1 Q This invention relates to the stabilization of vinyl halide resins, and particularly the vinyl halide resins which are polymers of at least 70- percent of vinyl halide, including thepolymers of '100 percent vinyl halide and the copolymers ofvinyl halides with other polymerizable monoolefinic compounds.

Vinyl halideresins generally will discolor when metal tartrate to the resin composition will enable the resin to resist the discoloration effect for sub- .stantial periods of time.

The vinyl halide resins which may be stabilized in accordancewith this invention include the polyvinyl halides, made by thepolymerization of any compound of the group consisting of, vinyl chloride, vinyl bromide, vinyl fluoride and vinyl iodide without the presence of other polymerizable mono-olefinic compounds. The invention is also useful in the prevention of discoloration upon heating in copolymers of from '70 to 100 percent of a vinyl halide with from 0 to percent of anotherpolymerizable mono-oleflnic compound. Although any polymerizable monoolefinic' compound which is compatible with the vinyl halide in polymeric form, that is, which forms copolymers therewith, may be stabilized, the

invention is particularly useful in the treatment The stabilization against discoloration upon heating is eifected by the addition of antimony alkali metal tartrates. Although any member of this class of compounds is useful, for obvious economic reasons the antimony potassium tartrate and the antimony sodium tartrate are preferred. The quantity of stabilizer used will depend upon the severity of the heating to which the vinyl resin-is to be subjected. Even traces of the agent will yield an improved product which will be useful where only mild-heating is to be en- I I countered. Although from 0.05 to 10 percentby the art.

' weight, based on the polymer 'any' of several methods.

content of the resin, will produce'useful compositions, generally it is desirable to use from 0.5 to 5 percent of the alkali metal tartrate. t

The stabilizing agent may be incorporated by It may be added to the solid resin and mixed therein by means of a roll -mill or other mixing machine adapted to blend solid plastic materials. The mixing machine may be heated during the mixing operation to render the compositions more plastic. Alternatively, the stabilizing agent may be dissolved in-any suitable solvent, and the. solution then mixed with the resin. The vinyl halide resin may be dissolved in 'a solvent, such as ethylene dichloride; and the stabilizing agent added to the solution and dispersed therein by meansof any stirring device. If the polymers or copolymers are prepared by polymerization in an aqueous emulsion, the stabilizing agent may be added and distributed through the polymer prior to coagulation. Any other method which permits a uniform distribution of the stabilizing agent throughout the p01- ym'ervmay be used. I

. The stabilized resins may be-used in the preparation of cast films or in the fabrication of molded or extruded shapes, which uses are well known to The stabilized vinyl halide resinsare particularly useful in the preparation of transparent or lightcolored articles in which discoloratlonupon heating is undesirable.

Further details of the invention are set forth with respect to thefollowing specific example.

Example Each of three 10 gram samples of a copolymer plated roll mill for 5 minutes at 140 F., and then for 5 minutes at 212 F. The coplymers were finally rolled into sheets 1 mm. in. thickness. Specimens-were cut from each of the three sheets and were tested by heating at C. for periods of time varying between A, hour and 4 hours. It

was found that the copolymer containing anti-" mony potassium tartrate was unaffected by the temperature of 135 C. throughout the'four hour period, while thecontrol copolymer and the copolymer containing antimony tartrate were i 1.'Avinyl halide coloration upon heating which comprises a polyboth discolored by the heat to about the same extent.

This application is a continuation-in-part of.

application Serial No. 502,311, filed September 14, 1943 now abandoned;

Although the invention has been described with respect to a specific example, it is not intended that the details thereof shall be construed as limitations upon the scope of the invention except to the extent incorporated in the following claims.

We claim;

resin capable of resisting dismer of from 'IO- -to 100 percent of vinyl halide and from up to 30 percent of 'mono-olefinic com-.

pound copolymerizable "with vinyl halide,. said 5; A'vinyl chloride resin capable of resisting .discoloration'upon heating which comprises a copolymer of 70 to 98 percent of vinyl chloride and from 2 to 30 percent of dialkyl chloromaleate, said resincontaining from 0.05 to percent by weight based on the copolymer. of

antimony potassium tartrate.

6. A vinyl halide resin capable of resisting discoloration upon heating which comprises a polymer of from '70 to 100 percent of vinyl halide and from up to 30 percent of mono-olefinic compolymer containing from 0.05 to 10' percent by weight based onthe polymer content of the resin of an antimony alkali metal tartrate.

21A vinyl chloride resin capablefof resisting discoloration upon heating whichcomprises a copolymer of- 70 to 98 percentgof vinyl chloride" and from 2 to 30 percent of mono-olefinic. compound copolymeriaable with vinyl chloride, said resin containing from 0.05- to 10 percent by .8. A,-vinyl chloride "resin capable of resisting discoloration. upon heating which comprises a weight based on the copolymer' of antimony poltassium -tartrate. r

- 3. A vinyl chloride resin capable of resisting discoloration upon heating. which comprises a oopolymer of '70 to 98 percent of vinyl chloride and from 2 to percent of dialkyl-fumarate, said resin containing from 0.05 to 10 percent by weight'based on the copolymer otantimony: potassium tartrate. r

4. A vinyl chloride resin capable of resisting copolymer of to percent vinyl chloride and 5 to 20 percent of dialkyl maleate, said resin containing from 0.5 1:05 percent .by'weight based o'nthe copolym'er, of antimony potassium'tar- .trate.

" 9. A vinyl chloride resin capable of resisting discoloration upon heating which comprises a' copolymer of 80 to 95 .percentvinyl chloride and -5 to 20 percent of .dialkyl chloromaleate. said resin containing from 0.5 to 5 percent by weight discoloration upon heating which comprises a copolymer of 70 to 98 percent of vinyl chloride and from 2 to 30 percent of'dialkyl" maleate", said resin containing from 0.05 to 10 percent by.

weight based on the copolyiner'of antimony po-' tassium tartrate.-

based on the copolymenof antimony potassium tartrate. FREDWcoxL JANIES WALLACE, JR.

No references cited. I 

